Express your answer as a mixed number simplified to lowest terms. $17\dfrac{3}{7}-9\dfrac{1}{7} = {?}$
Explanation: Separate the whole numbers from the fractional parts: $= {17} + {\dfrac{3}{7}} - {9} - {\dfrac{1}{7}}$ Bring the whole numbers together and the fractions together: $= {17} - {9} + {\dfrac{3}{7}} - {\dfrac{1}{7}}$ Subtract the whole numbers: $=8 + {\dfrac{3}{7}} - {\dfrac{1}{7}}$ Subtract the fractions: $= 8+\dfrac{2}{7}$ Combine the whole and fractional parts into a mixed number: $= 8\dfrac{2}{7}$